SHARP 20BM2
Service Manual

CONVERGENCE CRT CUT-OFF, BACKGROUND AND SUB-CONTRAST ADJUSTMENT
NO. Adjustment part Adjusting procedure conditions Waveform and others NO. Adjustment part Adjusting procedure conditions Waveform and others 1 CRT CUTOFF 1. Switch TV to VIDEO mode, BLUE BACK OFF, 1 CONVERGENCE 1. Receive the �Crosshatch Pattern� signal. ADJUSTMENT with NO VIDEO signal. CONTROL) 3. Connect the oscilloscope to Red OUT from IC801.(TP851 (14")/TP852 (20"/21")) R Range : 1 V/Div (DC) Sweep : 5 msec/Div
RGB 2. Turn the 6-pole magnet to a proper opening
1 V colours.

3.0Vdc

BGR

14BM2, 14BM2S/G 20BM2, 20BM2S/G 21BM2, 21BM2S/G

B G adjustment.) Static convergence

ADJUSTMENT 2. Using the remote controller, call NORMAL (I C BUS 2. Press R/C to set Picture Normal condition. (To be done mode.2 after the purity

1. Turn the 4-pole magnet to a proper opening

angle in order to superpose the blue and red Fig. 5-1

0 4. Adjust SCREEN VR, so that the tip of signal

angle in order to superpose the green colour reach 3.0 ±0.1 Vdc. Fig. 6 over the blue and red colours. G 2 SUB1. Call �SUB-BRI� in service mode. (Receive B Fig. 5-2 2 screen in the following steps. (I C BUS that line 1, 2 and 3 have the same darkness
B 2 3 and finally line 5 will be the brighter 1, 2 and 3 are in same black level. R

Dynamic convergence BRIGHTNESS Crosshatch pattern with 5 black level windows) 1. Adjust convergence on fringes of the ADJUSTMENT 2. Adjust the �SUB BRIGHT� bus data in order 1 2 3 4 5 wherelse 4 is slightly brighter than line 1, a) Fig. 5-1: Drive the wedge at point �a� and RGB CONTROL) swing the deflection coil upward. than line 4. b) Fig. 5-2: Drive the wedge at points �b� and R

G

Fig. 7 �c� and swing the deflection coil * 12,300°K X : 0.272 c) Fig. 5-3: Drive the �c� wedge deeper and BALANCE nal.

downward. 3 WHITE 1. Receive the �WHITE� pattern with BURST sigRefer to Page ????. Fig. 5-3 2. Press R/C to set Picture NORMAL condition. Y : 0.275 swing the deflection coil rightward. SERVICE
R (-) and TP603 (+). Y : 0.255
2

BGR MODE 3. Connect DC miliammeter between TP602 * 18,000°K X : 0.255 d) Fig. 5-4: Drive the �b� wedge deeper and

2. Fix all wedges on the CRT and apply glass (I C BUS 4. Check Beam current should be around 1,100 µA B & DRI-BS data to have a colour temperature *Note: Above Data can be UP/ magnet unit (purity, 4-pole, 6-pole magnets) * Note . 6. Receive �WHITE� pattern, WITH BURST signal, LOW HIGH Finally received the Red-only and Blue-only Wedge "a"
100° LUMINATE Y signal.

swing the deflection coil leftward. ADJUSTMENT G

tape over them. CONTROL) (20"&21") (14" around 800 µA). (MINOLTA COLOUR ANALYZER Fig. 5-4 of 12,300°K or 7,500°K (white). DOWN by Volume key. and magnet unit lock screw.

3. Apply lacquer to the deflection yoke lock screw, 5. Set it to service mode and adjust the DRI-GS, CA-100)

8
Wedge "c" Note: This adjustment must be done after "b"

and set BRIGHTNESS Y by generator, to ** 14" 10 200 cd/m2 signals to make sure there is no other colours (MINOLTA CA-100) by reducing 20"/21" 10 120 cd/m2 on the screen. About 7. Adjust �CUT-R� & �CUT-G� to get desired colour temperature. Then go back NORMAL mode Lacquer (HIGH BRIGHT**) to check colour temperature. If out 14� back to (1)

Fig. 5-5
4-pole magnet CRT neck

warming up the unit for 30 minutes or longer with a beam current over 700 (20"&21") µA. (For 14", the beam current should be 6-pole magnet over 500 µA) * Adjust DRI-GC/GW, DR-BC/BW as following data, after finishing DRI-BS and DRI-GS data * 12,300°K DRI-GW=�DRI-GS�-7 adjustment. DRI-BW=�DRI-BS�-7 DRI-RW=32 (FIXED), DRI-GW=�DRIGS�-7*, DRI-BW=�DRI-BS�-7* * 18,000°K DRI-GC=�DRI-GS� 20cm
40cm

Purity magnet DRI-GC=�DRI-GS�-7* DRI-RC=27

Lacquer (21") DRI-RC=25, DRI-BC=�DRI-BS�, DATA-5

Fig. 5-6 (14") 4 MAXIMUM 1. Receive the �Monoscope Pattern� signal. BEAM CHECK 2. Press R/C to set Picture NORMAL condition. 3. Connect the DC miliammeter between TP603 4. Beam current must be within 1,100 ±100µA

(+) and TP602 (�). (Full Scale: 3 mA Range) (21") 800 ± 100 µA(14") .

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